A secondary battery, which is easily applied to various product groups and has electrical characteristics such as high energy density, is universally applied not only for a portable device but also for an electric vehicle (EV) or a hybrid electric vehicles (HEV), an energy storage system or the like, which is driven by an electric driving source. The secondary battery is attracting attention as a new environment-friendly energy source for improving energy efficiency since it gives a primary advantage of reducing the use of fossil fuels and also does not generate by-products by the use of energy at all.
Secondary batteries widely used at the preset include lithium ion batteries, lithium polymer batteries, nickel cadmium batteries, nickel hydrogen batteries, nickel zinc batteries and the like. An operating voltage of the unit secondary battery cell, namely a unit battery cell, is about 2.5V to 4.2V. Therefore, if a higher output voltage is required, a plurality of battery cells may be connected in series to configure a battery pack. In addition, depending on the charge/discharge capacity required for the battery pack, a plurality of battery cells may be connected in parallel to configure a battery pack. Thus, the number of battery cells included in the battery pack may be variously set according to the required output voltage or the demanded charge/discharge capacity.
Meanwhile, when a plurality of battery cells are connected in series or in parallel to configure a battery pack, it is common to configure a battery module composed of a plurality of battery cells first, and then configure a battery pack by using a plurality of battery modules and adding other components.
In a battery module or a battery pack which includes a plurality of battery cells for high output and large capacity, ignition or explosion may occur due to heat generated during a charging/discharging process. Thus, a temperature sensor is generally mounted to the battery module in order to monitor the temperature of battery cells inside the battery module. The temperature sensor is inserted through the battery module and mounted at the inside of the battery module so as to be located near the battery cells inside the battery module for accurate temperature measurement.
Hereinafter, an assembly process for mounting a temperature sensor at a conventional battery module will be described in more detail with reference to FIG. 1.
FIG. 1 is a diagram for illustrating an assembly error of the temperature sensor of the conventional battery module.
Referring to FIG. 1, the conventional battery module 1 includes a battery cell assembly 2 having a plurality of battery cells 3, an interconnection board 5 mounted to an upper side of the battery cell assembly 2 to electrically connect the plurality of battery cells 3, a temperature sensor mounting groove 6 provided at the interconnection board, and a temperature sensor 7 inserted through the temperature sensor mounting groove 6 to measure the temperature of the battery cells 3 in the battery module 1.
However, in the conventional battery module 1, when the temperature sensor 7 is mounted, if an end 4 of the battery cell 3 is disposed at a bottom of the temperature sensor mounting groove 6, an end 8 of the temperature sensor 7 may frequently interfere with the end 4 of the battery cell 3. If the interference occurs, the temperature sensor 7 may not be easily mounted inside the battery module 1.
Also, when the interference occurs, if the temperature sensor 7 is continuously assembled for mounting the temperature sensor 7, for example by forcibly pushing the temperature sensor 7, the temperature sensor 7 may cause an assembling error or damage the battery cell 3.